Field of the Invention
The invention relates to a fan speed controlling method and an application thereof, and more particularly relates to a fan speed controlling method for adjusting a fan speed by predicting a temperature variation trend of an electronic apparatus and the electronic apparatus using the fan speed controlling method.
Description of Related Art
Internal parts (e.g. CPU) and/or devices (e.g. power supply) in an electronic apparatus are usually provided with heat sink devices (e.g. heat sinks and fans). Among these heat sink devices, the fan is an indispensable component because it is capable of dissipating heat generated by the internal parts and/or devices in the electronic apparatus to the outside of the housing of the electronic apparatus for the system of the electronic apparatus to operate normally.
Generally, the speed control signal provided for driving the fan may be a DC voltage or a pulse width modulation (PWM) signal. The fan speed (RPM) can be controlled by changing the level of the DC voltage or the duty cycle of the PWM signal.
However, even with the same speed control signal, an error in the fan speed may occur due to different fan specifications and/or wear (ageing) of the fan (the error may be up to hundreds or even thousands of revolutions). If there is a large error in the fan speed, the fan may not be able to effectively dissipate heat outside the housing of the electronic apparatus. As a result, the electronic apparatus may not function properly, which may very likely cause shutdown or unrecoverable damage to the hardware of the electronic apparatus.
In addition, according to the conventional fan speed controlling method, generally the fan speed is adjusted only based on the temperature inside the electronic apparatus. That is, the fan speed is increased only when the internal temperature of the electronic apparatus rises. With such a control mechanism, the internal temperature of the electronic apparatus may have become too high, or the circuits/devices inside the electronic apparatus may have been damaged due to high temperature when the temperature change is detected. It would be too late to increase the fan speed to maintain the normal operation of the electronic apparatus.